Gate valve

Abstract

To provide a gate valve for communicating opening parts with each other which lead to chambers adjacent to each other, or for individually opening / closing them, while reducing the whole height size of the gate valve.SOLUTION: In a gate valve 1, a first opening / closing mechanism 40 including a first cam groove 41 and a first cam roller 42 for reciprocating a valve assembly 10 between an intermediate position and a first closing position, and a second opening / closing mechanism 45 including a second cam groove 46 and a second cam roller 47 for reciprocating the valve assembly 10 between the intermediate position and a second closing position are provided in an individually operable manner. The first and second opening / closing mechanisms are arranged neighboring each other in a thickness direction D of the gate valve.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a gate valve to be disposed between a pair of chambers in a semiconductor manufacturing apparatus or the like, and more particularly to a gate valve disposed between a first chamber such as a process chamber and a second chamber such as a transfer chamber that are adjacent to each other, for interconnecting a first opening leading to the first chamber and a second opening leading to the second chamber, or for individually opening and closing the first and second openings. [Background technology]

[0002] Known examples of such gate valves include those disclosed in Patent Documents 1 and 2. These conventional gate valves include a valve assembly with a pair of valve plates, a valve shaft to the tip of which the valve assembly is attached, and a drive mechanism connected to the valve shaft. By operating the valve shaft with the drive mechanism, the valve assembly can be moved sequentially between a retracted position in which the first opening and the second opening are connected to each other, and a first closing position and a second closing position in which the pair of valve plates are brought into contact with the first opening and the second opening, respectively, to airtightly close the openings.

[0003] In such conventional gate valve drive mechanisms, one cam groove extends vertically, i.e., in the height direction along the axis of the valve shaft, on each of the left and right sides of the valve shaft to guide the operation of the valve shaft, which moves the valve assembly to each of the positions, from the left and right sides of the valve shaft.

[0004] However, if a single cam groove extending vertically were to be used to achieve this series of movements of the valve assembly to each of the positions, the height of the drive mechanism, and therefore the height of the entire gate valve, would become large.

[0005] In this way, if the overall height dimension of the gate valve is increased, it may not be possible to install the gate valve due to the space required for installing the gate valve between a pair of chambers. Therefore, from the perspective of miniaturizing the entire facility, it is desirable to reduce the overall height dimension of the gate valve as much as possible. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-197769 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-017655 Summary of the Invention [Problem to be solved by the invention]

[0007] Therefore, the technical object of the present invention is to provide a gate valve that is placed between adjacent chambers and that communicates with each other or opens and closes individually the openings leading to these chambers by operating a valve shaft with a drive mechanism to move a pair of valve plates attached to the valve shaft, and that can reduce the height dimension of the entire gate valve. [Means for solving the problem]

[0008] In order to achieve the above object, a gate valve according to the present invention is a gate valve that is disposed between a first chamber and a second chamber that are adjacent to each other, and that communicates between a first opening that leads to the first chamber and a second opening that leads to the second chamber, and that individually opens and closes the first and second openings. The gate valve comprises: a bonnet that separates the bonnet into an upper side and a lower side; a valve shaft that passes through the bonnet in an axial direction that extends vertically and has a tip end and a base end disposed on the upper and lower sides of the bonnet; a valve assembly formed by attaching a first valve plate and a second valve plate to the tip end of the valve shaft with their backs facing each other; and a valve drive mechanism that is connected to the base end of the valve shaft and that moves the valve assembly by operating the valve shaft, and the valve drive mechanism comprises: an air cylinder unit provided fixedly with respect to the bonnet and including first and second drive rods that can be driven independently; and a power transmission mechanism that connects the first and second drive rods with the valve shaft and transmits the driving force of the air cylinder unit to the valve shaft, whereby the valve assembly can be moved in the axial direction and in a thickness direction perpendicular to the axial direction to move the valve assembly to a first closing position for closing the first opening with the first valve plate, a second closing position for closing the second opening with the second valve plate, and a retracted position for connecting these openings to each other, and the power transmission mechanism includes a first cam frame connected to the first drive rod and operating together with the first drive rod, and a power transmission mechanism that connects the first and second drive rods with the valve shaft and transmits the driving force of the air cylinder unit to the valve shaft, whereby the valve assembly can be moved in the axial direction and in a thickness direction perpendicular to the axial direction to move the valve assembly to a first closing position for closing the first opening with the first valve plate, a second closing position for closing the second opening with the second valve plate, and a retracted position for connecting these openings to each other, toThe valve assembly includes a second cam frame connected to the second drive rod and operating together with the second drive rod, a lever member attached to the base end of the valve shaft, and a first opening / closing mechanism and a second opening / closing mechanism for individually reciprocating the valve assembly in the thickness direction, the first opening / closing mechanism having a first cam groove provided in either the first cam frame or the lever member, and a first cam roller provided in the other and slidably fitted in the first cam groove, and the second opening / closing mechanism having a second cam groove provided in either the second cam frame or the lever member, and a first cam roller provided in the other. and a second cam roller slidably fitted in the second cam groove, wherein the first cam roller reciprocates along the first cam groove in accordance with the reciprocating movement of the first drive rod, thereby causing the valve assembly to reciprocate in the thickness direction between a position occupied by the retracted position and a position occupied by the first closing position, and the second cam roller reciprocates along the second cam groove in accordance with the reciprocating movement of the second drive rod, thereby causing the valve assembly to reciprocate in the thickness direction between a position occupied by the retracted position and a position occupied by the second closing position. The gate valve has a width direction perpendicular to both the axial direction and the thickness direction, and in the first opening / closing mechanism and the second opening / closing mechanism, the first and second cam frames are disposed on both sides of the lever member in the width direction, and further, the first and second cam frames are arranged side by side in the thickness direction on both sides of the lever member. It is characterized by the following.

[0009] In the present invention, preferably ,before The first cam groove is formed with a first relief portion for allowing the first cam roller to escape when the valve assembly is moved to the second closed position, and the second cam groove is formed with a second relief portion for allowing the second cam roller to escape when the valve assembly is moved to the first closed position.

[0010] In addition, in the present invention, for example, the valve assembly may be further movable in the axial direction to an intermediate position that is located between the retracted position and the first and second closing positions, and the power transmission mechanism may include a first spring member and a second spring member interposed between the first and second drive rods and the lever member, such that the driving force of the first drive rod is transmitted to the lever member via the first spring member, and the driving force of the second drive rod is transmitted to the lever member via the second spring member. The power transmission mechanism may further include a stopper portion that stops the movement of the lever member in the axial direction when the valve assembly reaches the intermediate position from the retracted position by driving the air cylinder portion, and allows the opening / closing mechanism to move the lever member in a thickness direction, and when the axial movement of the lever member is stopped by the stopper portion, the opening / closing mechanism may individually drive the first and second drive rods to reciprocate the valve assembly individually between the intermediate position and the first and second closing positions.

[0011] In this case, the intermediate position is preferably provided at a position in the axial direction where the first and second closing positions are located. Preferably, the gate valve has a width direction perpendicular to both the axial direction and the thickness direction, and in the first opening / closing mechanism and the second opening / closing mechanism, the first and second cam frames are respectively arranged on both sides of the lever member in the width direction, and the first and second cam frames are respectively arranged side by side in the thickness direction on both sides of the lever member, and further, a first support frame and a second support frame are attached to the first drive rod and the second drive rod and are connected to the lever member so as to be able to move relatively thereto, the pair of first cam frames standing upright from the first support frame in the axial direction, and the first support frame and the lever member are connected by the first spring member between the pair of first cam frames in the width direction, and the pair of second cam frames standing upright from the second support frame in the axial direction, and the second support frame and the lever member are connected by the second spring member between the pair of second cam frames in the width direction.

[0012] More preferably, the first cam groove is formed with a first relief portion for allowing the first cam roller to escape when the valve assembly is moved from the intermediate position to the second closed position, and the second cam groove is formed with a second relief portion for allowing the second cam roller to escape when the valve assembly is moved from the intermediate position to the first closed position.

[0013] Furthermore, in the present invention, the power transmission mechanism may further include a guide frame fixed to the bonnet, and first and second guide mechanisms provided between the guide frame and the first and second cam frames to guide movement of these cam frames in the axial direction, wherein the first guide mechanism includes a first guide groove provided in either the guide frame or the first cam frame along the axis, and a first guide roller provided in the other of the two and slidably fitted into the first guide groove, and the second guide mechanism may include a second guide groove provided in either the guide frame or the second cam frame along the axis, and a second guide roller provided in the other of the two and slidably fitted into the second guide groove.

[0014] In this case, preferably, the guide frames are disposed on both sides of the lever member in the width direction, outside the first and second cam frames arranged side by side in the thickness direction.More preferably, on both sides of the lever member in the width direction, the air cylinder units hang down from the bonnet along the axis, the guide frames are disposed inside the air cylinder units in the width direction, the first drive rod and the second drive rod are arranged side by side in the thickness direction in each of the pair of air cylinder units, the first drive rods of the pair of air cylinder units are attached to both ends of the first support frame, and the second drive rods of the pair of air cylinder units are attached to both ends of the second support frame. [Effects of the Invention]

[0015] The gate valve according to the present invention has a first opening / closing mechanism and a second opening / closing mechanism each having a separate cam groove for individually reciprocating the valve assembly in the thickness direction between the retracted position and the first closing position, and between the retracted position and the second closing position. Therefore, according to the present invention, the height of the first and second cam frames each having the cam grooves can be reduced, thereby enabling the height of the entire gate valve to be reduced. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is an external view showing an embodiment of a gate valve according to the present invention. [Figure 2] FIG. 2 is an exploded perspective view of the valve drive mechanism separated into an air cylinder portion and a power transmission mechanism. [Figure 3] FIG. 3 is a cross-sectional view of a main part of the air cylinder unit of FIG. 2. [Figure 4] FIG. 3 is an exploded perspective view of the power transmission mechanism of FIG. 2. [Figure 5] 10 is a schematic diagram showing the relationship between the guide roller and the guide groove when the valve assembly is in the retracted position. FIG. [Figure 6] FIG. 10 is a schematic diagram showing the positional relationship between the cam roller and the cam groove when the valve assembly is in the retracted position. [Figure 7] FIG. 10 is a schematic diagram showing the relationship between the guide roller and the guide groove when the valve assembly is in an intermediate position. [Figure 8] FIG. 10 is a schematic diagram showing the positional relationship between the cam roller and the cam groove when the valve assembly is in an intermediate position. [Figure 9] 10 is a schematic view showing the relationship between the guide roller and the guide groove when the valve assembly is in the first closed position. FIG. [Figure 10] 10 is a schematic diagram showing the positional relationship between the cam roller and the cam groove when the valve assembly is in a first closed position. FIG. [Figure 11] 10 is a schematic view showing the relationship between the guide roller and the guide groove when the valve assembly is in the second closed position. FIG. [Figure 12]10 is a schematic diagram showing the positional relationship between the cam roller and the cam groove when the valve assembly is in the second closed position. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0017] The gate valve 1 shown in FIG. 1, which is one embodiment of the present invention, is arranged between a process chamber (first chamber) 2 and a transfer chamber (second chamber) 3 adjacent to each other in, for example, a semiconductor manufacturing apparatus, as shown in FIGS. 5 to 12, to interconnect a first opening 4a leading to the first chamber 2 and a second opening 4b leading to the second chamber 3, or to open and close them individually.

[0018] The gate valve 1 comprises: a bonnet 5 that forms a boundary between an upper region U and a lower region B and separates the two regions U, B; a valve shaft 6 that penetrates the bonnet 5 in the direction of an axis L that extends vertically and has a tip end 6a located in the upper region U of the bonnet 5 and a base end 6b located in the lower region B; a valve assembly 10 formed by arranging a first valve plate 11 and a second valve plate 12 side by side on the tip end 6a of the valve shaft 6 and facing back to back; and a valve drive mechanism 20 that is connected to the base end 6b of the valve shaft 6 and moves the valve assembly 10 by operating the valve shaft 6.

[0019] The bonnet 5 is formed of a substantially rectangular metal plate that is long in a width direction W perpendicular to the axis L, and has a first surface (upper surface) 5a facing an upper region U and a lower region B 5 to 12, the bonnet 5 forms the bottom wall of a hollow valve box 7 that is open downward. The valve box 7 has side walls 8 that surround the valve box 7 on all four sides about the axis L, and the bonnet 5 is detachably attached to the lower end of the side wall 8 in the direction of the axis L, so that the opening at the lower end of the side wall 8 can be airtightly closed.

[0020] By attaching the bonnet 5 to the valve box 7 in this manner, the valve assembly 10 attached to the tip 6a of the valve shaft 6 is accommodated in the valve box 7. The through-hole 5c has an inner diameter slightly larger than the outer diameter of the valve shaft 6 to allow movement of the valve assembly 10 in the axial L direction and in the thickness direction D (i.e., the direction in which the first and second valve plates 11, 12 in the valve assembly 10 are arranged side by side) perpendicular to the axial L direction and the width direction W, The aforementioned It is installed through the center of the hood 5.

[0021] The valve assembly 10 includes the first and second valve plates 11, 12 formed in a generally rectangular shape elongated in the width direction W, and first and second clamp members 13, 14 for detachably fixing the valve plates 11, 12 to the tip end 6a of the valve shaft 6. The first and second valve plates 11, 12 have a first seal surface 11a and a second seal surface 12a that are back-to-back and parallel to each other in the thickness direction D, and annular valve seal members 11b, 12b such as O-rings are attached to the outer peripheries of the seal surfaces 11a, 12a. Note that the pair of valve seal surfaces 11a, 12a do not necessarily have to be parallel to each other.

[0022] The first clamp member 13 is engaged by projections and recesses from above between the first valve plate 11 and the tip of the valve shaft 6 and between the second valve plate 12 and the tip of the valve shaft 6 at two locations in the center of the valve assembly 10 in the width direction W. The second clamp member 14 is engaged by projections and recesses from above between the first valve plate 11 and the second valve plate 12 at both ends of the valve assembly 10 in the width direction W. At this time, a spacer member 15 is sandwiched between the first and second valve plates 11, 12 below the second clamp member 14 by the inner surfaces of the pair of valve plates 11, 12 (FIGS. 5 to 12).

[0023] Then, when the first clamp member 13 is fixed to the tip of the valve shaft 6 from above with a fastening bolt 13a while the first and second valve plates 11, 12 are engaged with the base end of the tip portion 6a from above, the inclined surfaces with different inclinations are pressed against each other at each of the engagement portions. As a result, at the center of the valve assembly 10 in the width direction W, the tip portion 6a of the valve shaft 6 is sandwiched between the inner surfaces of the first and second valve plates 11, 12, and the valve plates 11, 12 and the valve shaft 6 are fastened to each other in the thickness direction D.

[0024] On the other hand, at both ends of the valve assembly 10 in the width direction W, when the first and second valve plates 11, 12 are engaged from above with the base end of the second clamp member 14 in a concave-convex manner, and the second clamp member 14 is fixed to the tip of the spacer member 15 from above with fastening bolts 14a, inclined surfaces with different inclinations are pressed against each other at each of the concave-convex engagement portions. As a result, at both ends of the valve assembly 10 in the width direction W, the valve plates 11, 12 and the spacer member 15 are fastened to each other in the thickness direction D with the spacer member 15 sandwiched between the inner surfaces of the first and second valve plates 11, 12.

[0025] Note that a specific mounting structure for the first and second valve plates 11, 12 to the valve shaft 6 is described in a Japanese application (Patent Application No. 2021-168188) previously filed by the applicant, and furthermore, in this application, the structure of the valve assembly 10 and the mounting structure for the valve plates 11, 12 to the valve shaft 6 are not limited to the above-described structure, and various well-known structures can be adopted. Therefore, a more specific description thereof will be omitted here.

[0026] 5 to 12, the valve box 7 is attached between the first chamber 2 and the second chamber 3, and a top wall 9 that airtightly closes the upper opening of the side wall 8 in the direction of axis L is detachably attached to the upper opening of the side wall 8. By detachably attaching the top wall 9 to the side wall 8 in this manner, various operations such as removing the valve plates 11 and 12 can be performed through the upper opening of the side wall 8 when performing maintenance on the valve assembly 10, such as replacing the valve seal members 11b and 12b of the valve plates 11 and 12.

[0027] The side wall 8 of the valve box has a first inner surface 8a and a second inner surface 8b that are parallel to each other and face each other across the axis L in the thickness direction D. The first inner surface 8a has the first opening 4a that communicates with the first chamber 2, and the second inner surface 8b has the second opening 4a that communicates with the second chamber 2. Chamber The first and second openings 4a and 4b are disposed opposite each other in the thickness direction D. The first and second inner surfaces 8a and 8b are provided around the first and second openings 4a and 4b with first and second seal surfaces 11a and 11b of the valve assembly 10. ,12a Each valve seal member 11b ,12b A valve seat portion 4c for moving the valves in contact with and away from each other is formed so as to surround the openings 4a and 4b.

[0028] The gate valve 1 mounted on such a valve box 7 can move the valve assembly 10 within the valve box 7 to a retracted position ( FIGS. 5 and 6 ) disposed on the axis L for connecting the first opening 4 a and the second opening 4 b to each other, a first closing position ( FIGS. 9 and 10 ) for airtightly closing the first opening 4 a with the first valve plate 11, a second closing position ( FIGS. 11 and 12 ) for airtightly closing the second opening 4 b with the second valve plate 12, and an intermediate position ( FIGS. 7 and 8 ) set at the same height position on the axis L as the first and second closing positions, by operating the valve shaft 6 with the valve drive mechanism 20. Note that in this intermediate position, the valve drive element 10 is spaced apart from both the first and second openings 4 a and 4 b.

[0029] As shown in Figures 1 to 3, the valve drive mechanism 20 that operates the valve assembly 10 in this manner includes an air cylinder section 21 equipped with a first drive rod 22a and a second drive rod 23a that can be driven individually, and a power transmission mechanism 30 that connects the first drive rod 22a and the second drive rod 23a to the base end of the valve shaft 6 and transmits the drive force of the air cylinder section 21 to the valve shaft 6.

[0030] 3, the air cylinder section 21 has one cylinder body 24, first and second cylinder holes 22b, 23b extending along the axis L within the cylinder body 24, and a pair of pistons 22c, 23c slidably provided within the pair of cylinder holes 22b, 23b, respectively, and base ends of the first and second drive rods 22a, 23a are fixed to the pair of pistons 22c, 23c. The air cylinder section 21 hangs down from the bonnet 5 along the axis L by fixedly attaching the head side end of the cylinder body 24 to a second surface 5b of the bonnet 5 facing downward.

[0031] As a result, the tip ends of the first and second drive rods 22a, 23a extend downwardly and are movable forward and backward from the rod-side end of the cylinder body 24. In addition, air can be supplied to and exhausted from the first and second cylinder holes 22b, 23b individually, so that the first drive rod 22a and the second drive rod 23a can be driven individually.

[0032] As shown in FIGS. 2 and 4, the power transmission mechanism 30 includes a first support frame 31 and a second support frame 32 attached to the first drive rod 22 a and the second drive rod 23 a, a first cam frame 33 and a second cam frame 34 fixedly attached to the first and second support frames 31 and 32 and extending along the axis L, and a base end portion of the valve shaft 6. 6b The power transmission mechanism 30 has a lever member 35 fixedly attached to the valve shaft 6 and moving integrally with the valve shaft 6, and a first spring member 36 and a second spring member 37 connecting the first and second support frames 31, 32 and the lever member 35 so that they can be displaced relative to each other. As will be described below, the power transmission mechanism 30 is particularly formed symmetrically in the thickness direction D with respect to a central plane that includes the axis L and extends in the width direction W. hand Furthermore, the gate valve 1 is formed symmetrically in the width direction W with respect to a central plane that includes the axis L and extends in the thickness direction D. In this embodiment, the entire gate valve 1 is also formed symmetrically in the width direction W and the thickness direction D in the same manner.

[0033] In this way, by interposing (specifically, compressing) the first and second spring members 36, 37 between the first and second support frames 31, 32 and the lever member 35, respectively, the driving forces of the first and second drive rods 22a, 23a are individually transmitted to the lever member 35 through the first and second spring members 36, 37, and as a result, the first and second drive rods 22a, 23a and the lever member 35 can each be moved relative to one another.

[0034] More specifically, in this embodiment, the air cylinder unit 21 is fixedly attached to the bonnet 5 with the first cylinder bore 22b, its piston 22c, and the first drive rod 22a positioned at the first closing position, and the second cylinder bore 23b, its piston 23c, and the second drive rod 23a positioned at the second closing position. That is, the first and second drive rods 22a, 23a are adjacent to each other in the thickness direction D, with the first drive rod 22a positioned at the first closing position and the second drive rod 23a positioned at the second closing position. A pair of such air cylinder units 21 is disposed on both sides of the valve shaft 6 in the width direction W (i.e., across the axis L). However, the number and arrangement of the air cylinder units 21 are not limited to those in this embodiment.

[0035] The first and second support frames 31, 32 are formed from metal plates that are long in the width direction W, and in the width direction W, the respective tip ends of the first drive rods 22a of the pair of air cylinder sections 21 are attached to both ends of the first support frame 31 that are sandwiched between the axis L, and the respective tip ends of the second drive rods 23a of the pair of air cylinder sections 21 are attached to both ends of the second support frame 32 that are sandwiched between the axis L.

[0036] Therefore, the first and second support frames 31, 32 are arranged side by side in the thickness direction D, with the first support frame 31 located on the first closing position side and the second support frame 32 located on the second closing position side. Furthermore, spring seats 31a, 32a are recessed in the central portions of the support frames 31, 32 in the width direction W, and these spring seats 31a, 32a receive the lower ends of the first spring member 36 and the second spring member 37 in the axial L direction.

[0037] The first and second cam frames 33, 34 are both formed from metal plates, and have inner surfaces 33a, 34a and outer surfaces 33b, 34b that extend in the axial L direction and thickness direction D and face each other. The pair of first cam frames 33 are fixedly erected upward from both sides of the first support frame 31 across the axis L, between the pair of air cylinder sections 21, and similarly, the pair of second cam frames 34 are fixedly erected upward from both sides of the second support frame 32 across the axis L, between the pair of air cylinder sections 21.

[0038] Therefore, in the thickness direction D, the first and second cam frames 33, 34 are arranged side by side, with the first cam frame 33 disposed on the first closed position side and the second cam frame 34 disposed on the second closed position side. These adjacent cam frames 33, 34 are formed symmetrically in the thickness direction D with respect to a center plane that includes the axis L and extends in the width direction W. Meanwhile, in each pair of the first and second cam frames 33, 34, the inner surfaces 33a, 34a face each other, and the outer surfaces 33b, 34b face back to back. These pair of first cam frames 33 and pair of second cam frames 34 are formed symmetrically in the thickness direction D with respect to a center plane that includes the axis L and extends in the thickness direction D. center They are arranged symmetrically in the width direction W with respect to the surface.

[0039] The lever member 35 is formed from a metal block having an H-shape in front view, and has, at its upper end in the direction of axis L, an upper recess 35a formed in the center in the width direction W and a pair of upper protrusions 35b protruding from both sides thereof, and, at its lower end in the direction of axis L, a lower recess 35c formed in the center in the width direction W and a pair of lower protrusions 35d protruding from both sides thereof. Also, the lever member 35 has, at both ends in the width direction W, a pair of side surfaces 35e facing each other.

[0040] The base end 6b of the valve shaft 6 is fixedly attached to the upper recess 35a, and the valve shaft 6 is airtightly surrounded by a cylindrical bellows 6c between the upper recess 35a of the lever member 35 and the through-hole 5c of the bonnet 5. The upper ends of the first and second spring members 36, 37 in the axial L direction are attached to the lower recess 35c.

[0041] The first and second spring members 36, 37 are formed by metal coil springs and are capable of supporting the weight of the valve assembly 10 and the lever member 35. spring Therefore, in the process of moving the assembly 10 from the retracted position (FIGS. 5 and 6) to the intermediate position (FIGS. 7 and 8) along the axis L, the spring forces of the spring members 36 and 37 allow the drive rods 22a and 23a of the air cylinder portion 21 and the valve assembly 10 to move together.

[0042] Then, in the process of moving the assembly 10 in the thickness direction D from the intermediate position to the first and second closed positions by the opening and closing mechanisms 40, 45 described below, the spring members 36, 37 are compressed and deformed by the driving force of the drive rods 22a, 23a. As a result, the valve assembly 10 can be moved relative to the drive rods 22a, 23a in the thickness direction D, which is perpendicular to the operating direction (axis L direction) of the drive rods 22a, 23a.

[0043] Furthermore, the power transmission mechanism 30 is used for operation of the valve shaft 6 and the valve assembly 10 in the thickness direction D, and is provided with a first opening / closing mechanism 40 and a second opening / closing mechanism 45 that individually reciprocate the valve assembly 10 in the thickness direction D between a position occupied by the retracted position and a position occupied by the first closing position, and between a position occupied by the retracted position and a position occupied by the second closing position, and is used for guiding the reciprocating movement of the first and second cam frames 33, 34 in the axial direction L. The cam frame 33, 34 has a first guide mechanism 50 and a second guide mechanism 55 that guide the reciprocating movement of the cam frames 33, 34 in the axial L direction between the retracted position and the intermediate position, and a stopper portion 60 that abuts the lever member 35 against the second surface 5b of the bonnet 5 at the intermediate position, thereby preventing the lever member 35, the valve shaft 6, and the valve assembly 10 from moving in the axial L direction, while allowing them to move in the thickness direction D.

[0044] The first and second opening and closing mechanisms 40, 45 are formed across the first and second cam frames 33, 34 and the lever member 35 disposed between the cam frames 33, 34, and more specifically, are provided between the inner surfaces 33a, 34a of the first and second cam frames 33, 34 and a side surface 35e of the lever member 35 opposing the inner surfaces 33a, 34a. Furthermore, the opening and closing mechanisms 40, 45 are arranged side by side in the thickness direction D, with the first opening and closing mechanism 40 disposed on the first closing position side and the second opening and closing mechanism 45 disposed on the second closing position side.

[0045] The first opening and closing mechanism 40 has a first cam groove 41 recessed in the inner surface 33a of the first cam frame 33 and a first cam roller 42 provided on the side surface 35e of the lever member 35 opposing the first cam groove 41, with the first cam roller 42 slidably fitted in the first cam groove 41. On the other hand, the second opening and closing mechanism 45 has a second cam groove 46 recessed in the inner surface 34a of the second cam frame 34 and a second cam roller 47 provided on the side surface 35e of the lever member 35 opposing the first cam groove 41, with the second cam roller 47 slidably fitted in the second cam groove 46. In this embodiment, such first and second opening and closing mechanisms 40, 45 are provided in pairs on both side surfaces 35e of the lever member 35.

[0046] The first cam groove 41 has a start position S1 on the upper end side in the direction of axis L and a terminal position E1 on the lower end side in the direction of axis L, and the terminal position E1 is located closer to the first closing position than the start position S1 in the thickness direction D. That is, the first cam groove 41 has a profile that slopes toward the first closing position from the start position S1 on the upper end side toward the terminal position E1 on the lower end side. When the first cam roller 42 is in the start position S1, the valve assembly 10 is positioned on the axis L, and when the first cam roller 42 is in the terminal position E1, the valve assembly 10 is positioned in the first closing position. In this embodiment, two first cam grooves 41 having the same shape are formed at the upper and lower ends of the first cam frame 33, and the first cam groove 41 located on the upper end side opens to the upper end surface of the first cam frame 33 at the start position S1.

[0047] On the other hand, the second cam groove 46 has a start position S2 on the upper end side in the direction of the axis L and a terminal position E2 on the lower end side in the direction of the axis L, and in the thickness direction D, the terminal position E2 is disposed closer to the second closing position than the start position S2. That is, the second cam groove 46 has a profile that slopes toward the second closing position from the start position S2 on the upper end side toward the terminal position E2 on the lower end side. When the second cam roller 47 is at the start position S2, the valve assembly 10 is disposed on the axis L, and when the second cam roller 47 is at the terminal position E2, the valve assembly 10 is disposed at the second closing position. In this embodiment, two of the 2 Cam groove 46 The above 2 Cam Frame 34 The second cam groove 46 disposed on the upper end side of the second cam frame 34 opens into the upper end surface of the second cam frame 34 at the start position S2.

[0048] In this way, when one of the first and second cam frames 33, 34 is moved upward in the direction of axis L relative to the lever member 35, the cam rollers fitted in the cam grooves of the moved cam frame move along the cam grooves from the start position S to the end position E. This causes the lever member 35 to be displaced in the thickness direction D toward either the first closing position or the second closing position, and at the same time, the cam roller fitted in the other remaining cam frame must also be displaced the same distance in the thickness direction D.

[0049] Therefore, in this gate valve 1, all of the cam grooves 41 (two, upper and lower) formed in the first cam frame 33 have first recesses 41a recessed in the thickness direction D from the starting end position S1 toward the second blocking position, and all of the cam grooves 46 (two, upper and lower) formed in the second cam frame 34 have second recesses 46a recessed in the thickness direction D from the starting end position S2 toward the first blocking position.

[0050] Furthermore, sliding members 33c, 34c made of a resin material are provided on the upper and lower sides of the inner surfaces 33a, 34a of the first and second cam frames 33, 34, respectively, for sliding against both side surfaces 35e of the lever member 35. Meanwhile, sliding members 33c, 34c made of a resin material are also provided on the upper and lower sides of the outer surfaces 33b, 34b of the first and second cam frames 33, 34, respectively, for sliding against guide surfaces 25a of a guide frame 25, which will be described later. However, the number and positions of the sliding members 33c, 34c are not limited to this.

[0051] Furthermore, the power transmission mechanism 30 has a guide frame 25 fixedly attached to the bonnet 5 between the air cylinder portion 21 and the cam frames 33, 34, and hanging down from the second surface 5b thereof, and the guide frame 25 has a guide surface 25a facing the outer surfaces 33b, 34b of the cam frames 33, 34. In this embodiment, a pair of such guide frames 25 are arranged on both sides of the axis L in the width direction W, and the guide frame 25 is formed integrally with the cylinder body 24 of the air cylinder portion 21 adjacent to it in the width direction W.

[0052] The first and second guide mechanisms 50, 55 are formed across the guide frame 25 and the adjacent first and second cam frames 33, 34, and more specifically, are provided between the guide surface 25a of the guide frame 25 and the outer surfaces 33b, 34b of the first and second cam frames 33, 34 that face the guide surface 25a. That is, the guide mechanisms 50, 55 are arranged side by side in the thickness direction D, with the first guide mechanism 50 located on the first closing position side and the second guide mechanism 55 located on the second closing position side.

[0053] The first guide mechanism 50 has a first guide groove 51 recessed in the outer surface 33b of the first cam frame 33 and a first guide roller 52 provided on the opposing guide surface 25a of the guide frame 25, with the first guide roller 52 slidably fitted in the first guide groove 51. On the other hand, the second guide mechanism 55 has a second guide groove 56 recessed in the outer surface 34b of the second cam frame 34 and a second guide roller 57 provided on the opposing guide surface 25a of the guide frame 25, with the second guide roller 57 slidably fitted in the second guide groove 56. In this embodiment, the first guide mechanism 50 is provided on both outer surfaces 33b of the pair of first cam frames 33, and the second guide mechanism 55 is provided on both outer surfaces 34b of the pair of second cam frames 34, respectively.

[0054] The first guide groove 51 extends linearly from the upper end to the lower end of the first cam frame 33 along the axis L, and in this embodiment, the upper end of the guide groove 51 opens in the upper end surface of the first cam frame 33. Similarly, the second guide groove 56 extends linearly from the upper end to the lower end of the second cam frame 34 along the axis L, and in this embodiment, the upper end of the guide groove 56 opens in the upper end surface of the second cam frame 34. These guide grooves 51, 56 have the same length in the direction of the axis L. Furthermore, the sum of the depths of the cam grooves 41, 46 and the guide grooves 51, 56 formed in the cam frames 33, 34, respectively, is smaller than the length between the inner surfaces 33a, 34a and the outer surfaces 33b, 34b of the cam frames 33, 34, and the cam grooves 41, 46 and the guide grooves 51, 56 are arranged to partially overlap in the thickness direction D. Therefore, an increase in the dimensions of the valve drive mechanism 20 and the power transmission mechanism 30 in the thickness direction D is suppressed.

[0055] The first guide rollers 52 are provided in pairs, one above the other, along the axis L on the first closed position side of the guide surface 25a of the guide frame 25, and the second guide rollers 57 are also provided in pairs, one above the other, along the axis L on the second closed position side of the guide surface 25a. The distance in the axial L direction between the pair of upper and lower first guide rollers 52 is shorter than the length in the axial L direction of the first guide groove 51, and the distance in the axial L direction between the pair of upper and lower second guide rollers 57 is shorter than the length in the axial L direction of the second guide groove 56. The lengths in the axial L direction of the first and second guide grooves 51, 56 are greater than the sum of the distance in the axial L direction between the retracted position and the intermediate position and the distance in the axial L direction between the start end positions S1, S2 and the end end positions E1, E2 of the cam grooves 41, 46.

[0056] The stopper portions 60 are provided on the upper end surfaces 35f of the pair of upper protrusions 35b of the lever member 35, and are spaced apart from each other in the thickness direction D to The bonnet 5 has stop rollers 61 that can roll relative to the valve shaft 6, and cushions 62 (FIGS. 5 and 6) that are provided at portions of the second surface (lower surface) of the bonnet 5 that face the stop rollers 61. That is, in the width direction W, pairs of stop rollers 61 and cushions 62 are provided on both the left and right sides of the valve shaft 6. By doing so, the stop rollers 61 can be easily moved relative to the bonnet 5. 5 When the shock is applied to the surface of the vehicle, the shock can be absorbed by the cushion 62.

[0057] 5 to 12, when the valve assembly 10 moves upward along the axis L from the retracted position to the intermediate position due to the upward retraction of the first or second drive rod 22a, 23a, a stop roller 61 provided at the upper end of the lever member comes into contact with a cushion 62 provided on the second surface 5b of the bonnet 5, thereby stopping the upward movement of the valve assembly 10 along the axis L. Subsequently, the first opening / closing mechanism 40 or the second opening / closing mechanism 45As a result, when the valve assembly 10 moves in the thickness direction D from the intermediate position to the first blocking position or the second blocking position, the stop roller 61 in contact with the cushion 62 rolls on the cushion 62 in the thickness direction D as the valve assembly 10 moves.

[0058] As described above, in the gate valve 1, the first opening / closing mechanism 40, which includes the first cam groove 41 and the first cam roller 42 and reciprocates the valve assembly 10 between the intermediate position and the first closed position, and the second opening / closing mechanism 45, which includes the second cam groove 46 and the second cam roller 47 and reciprocates the valve assembly 10 between the intermediate position and the second closed position, are disposed adjacent to each other in the thickness direction D. In this manner, the gate valve 1 according to this embodiment, in which the valve assembly 10 can be moved individually to the first closed position and the second closed position using two sets of cam grooves 41, 46 and cam rollers 42, 47, can reduce the height of the cam frames 33, 34 compared to a conventional gate valve in which a single set of cam groove and cam roller is used to sequentially move the valve assembly to the first closed position and the second closed position. As a result, the height of the valve drive mechanism 20 can be reduced, and ultimately the height of the entire gate valve 1 can be reduced.

[0059] The operation of the gate valve 1 having such a configuration will be described. As shown in Figures 5 and 6, when the valve assembly 10 is in the retracted position, the first and second drive rods 22a, 23a of the air cylinder portion 21 are both advanced to the lower stroke ends. In this state, the spring forces (spring rigidity) of the first and second spring members 36, 37 cause the lever Component 35 are integrally supported on the first and second support frames 31, 32, and the first and second cam rollers 42, 47 are disposed at the start positions S1, S2 of the first and second cam grooves 41, 46 by the resilience of the spring members 36, 37. As a result, the drive rods 22a, 23a and the valve assembly 10 are supported by the support frames 31, 32, the cam frames 33, 34 and the lever members 35Further, only the lower guide rollers 52, 57 of the pair of upper and lower first guide rollers 52 and the pair of upper and lower second guide rollers 57 are fitted into the first and second guide grooves 51, 56, respectively.

[0060] Next, from this state, when air is supplied to the first cylinder hole 22b of the air cylinder portion 21 to drive the first drive rod 22a backward in the direction of axis L, a "rod side assembly" consisting of the first and second drive rods 22a, 23a, the first and second support frames 31, 32, and the first and second cam frames 33, 34, and a "shaft side assembly" consisting of the lever member 35, the valve shaft 6, and the valve assembly 10, move integrally upward in the direction of axis L. Then, the valve assembly 10 moves upward on the axis L from the retracted position and reaches the intermediate position (the first and second openings of the valve box 7) shown in FIGS. 7 and 8. Department The first and second valve plates 11 and 12 face the openings 4a and 4b, respectively, and the valve seal members 11b and 12b of these valve plates are fitted to the valve seats 11a and 12b of the openings 4a and 4b. Department 4c).

[0061] During this time, as shown in FIG. 5, both the first and second cam frames 33, 34 are guided along the axis L by the lower first and second guide rollers 52, 57 fitted in the first and second guide grooves 51, 56. Therefore, the valve shaft 6 can be raised along the axis L without tilting with respect to the axis L. Then, when the valve assembly 10 reaches the intermediate position, the upper first and second guide rollers 52, 57 also fit into the first and second guide grooves 51, 56 from their upper openings, as shown in FIG. 7. At the same time, the stop roller 61 of the lever member 35 abuts against the cushion 62 of the bonnet 5, thereby stopping the upward movement of the "shaft-side assembly" in the direction of the axis L at that position, and the upward movement of the valve assembly 10 in the direction of the axis L from the retracted position stops at the intermediate position.

[0062] Therefore, when the valve assembly 10 is in the intermediate position as described above, if the supply of air to the first cylinder bore 22b continues, the "first assembly" of the "rod side assembly", which is made up of the first drive rod 22a, first support frame 31, and first cam frame 33, continues to rise further while compressing the first spring member 36, while the "second assembly" made up of the second drive rod 23a, second support frame 32, and second cam frame 34 stops in that position.

[0063] As a result, the pair of upper and lower first cam grooves 41 formed in the first cam frame 33 rise relative to the pair of upper and lower first cam rollers 42 fitted therein, and the cam grooves 41 rise until the first drive rod 22a reaches the upper stroke end. At this time, as shown in Figure 10, within the pair of upper and lower first cam grooves 41, the pair of upper and lower first cam rollers 42 that were at the start end position S1 each move to the end position E1, and at that time, these first cam rollers 42 move toward the first closing position in the thickness direction D perpendicular to the axial direction L, following the respective cam grooves 41.

[0064] 9 and 10, the entire "shaft-side assembly" including the valve assembly 10 is displaced in the thickness direction D perpendicular to the axis L from the intermediate position to the first closing position where the first valve plate 11 closes the first opening 4a of the valve box 7. At this time, the pair of upper and lower second cam rollers 47 provided on the lever member 35 also move toward the first closing position in conjunction with the movement of the "shaft-side assembly", and as described above, move within the second cam groove 46 from the start end position S2 to the second relief portion 46a recessed on the first closing position side of the start end position S2.

[0065] Conversely, when air is supplied to the second cylinder bore 23b from the retracted position of the valve assembly 10 shown in Figures 5 and 6, the second drive rod 23a is driven to retract upward in the direction of axis L, and the valve assembly 10 moves to the intermediate position shown in Figures 7 and 8, similar to the case where the first drive rod 22a is driven to retract. When the supply of air to the second cylinder bore 23b is continued while the valve assembly 10 is in the intermediate position, the "second assembly" of the "rod-side assembly" continues to rise while compressing the second spring member 37, while the "first assembly" stops at that position.

[0066] Then, the pair of upper and lower second cam grooves 46 formed in the second cam frame 34 rise relative to the pair of upper and lower second cam rollers 47 fitted therein, and the cam grooves 46 rise until the second drive rod 23a reaches the upper stroke end. At this time, as shown in FIG. 12, the pair of upper and lower second cam grooves 46 Within the cam groove 46, a pair of upper and lower second cam rollers 47 that were at the starting position S2 move to the terminal position E2, and at that time, these second cam rollers 47 move toward the second blocking position in the thickness direction D that is perpendicular to the axial direction L, following the respective cam grooves 46.

[0067] 11 and 12, the entire "shaft-side assembly" including the valve assembly 10 is displaced in the thickness direction D perpendicular to the axis L from the intermediate position to the second closing position where the second valve plate 12 closes the second opening 4b of the valve box 7. At this time, the pair of upper and lower first cam rollers 42 provided on the lever member 35 also move toward the second closing position in conjunction with the movement of the "shaft-side assembly", and as described above, move within the first cam groove 41 from the start end position S1 to the first relief portion 41a recessed on the second closing position side of the start end position S1.

[0068] In addition, when returning the valve assembly 10 from the first or second closing position (Figures 9 to 12) to the retracted position (Figures 5 and 6) via the intermediate position (Figures 7 and 8), the operation can be reversed from the above-mentioned steps.

[0069] As described above, in the gate valve 1, the valve assembly 10 is The aforementioned When the valve assembly 10 is displaced from the intermediate position to the second closed position, it can be displaced directly to the second closed position without passing through the first closed position as in the conventional valve assembly, which results in extremely excellent operability of the valve assembly 10. Furthermore, when the valve assembly 10 is displaced from the intermediate position to the first and second closed positions, the entire "shaft-side assembly" is moved in the thickness direction D perpendicular to the axis L, which makes it possible to suppress twisting of the valve seal members 11b, 12b and generation of wear powder when the first and second valve plates 11, 12 are moved toward and away from the first and second openings 4a, 4b of the valve box 7.

[0070] Although the embodiments of the present invention have been described in detail above, it goes without saying that the present invention is not limited to these embodiments, and various design changes can be made without departing from the spirit of the present invention. For example, in this embodiment, a "first assembly" consisting of the first drive rod 22a, the first support frame 31, and the first cam frame 33, and a "second assembly" consisting of the second drive rod 23a, the second support frame 32, and the second cam frame 34 are arranged side by side in the thickness direction D, with the "first assembly" positioned on the first blocking position side and the "second assembly" positioned on the second blocking position side, but conversely, the "first assembly" may be arranged on the second blocking position side and the "second assembly" may be arranged on the first blocking position side.

[0071] In addition, in this embodiment, the first and second cam grooves 41, 46 are provided in the first and second cam frames 33, 34, and the first and second cam rollers 42, 47 are provided in the lever member 35, but conversely, the cam grooves 41, 46 may be provided in the lever member 35, and the cam rollers 42, 47 may be provided in the cam frames 33, 34. In this embodiment, the first and second guide grooves 51, 56 are provided in the cam frames 33, 34, and the first and second guide rollers 52, 57 are provided in the guide frame 25 formed integrally with the cylinder body 24, but conversely, the guide grooves 51, 56 may be provided in the guide frame 25, and the guide rollers 52, 57 may be provided in the cam frames 33, 34. It is also possible to form the guide frame 25 separately from the cylinder body 24.

[0072] Furthermore, in this embodiment, the pair of upper and lower cam grooves 41, 46 formed in the cam frames 33, 34 have the same profile, so that when the valve assembly 10 is displaced from the intermediate position to the first and second closed positions, the entire "shaft-side assembly" is moved in the thickness direction D perpendicular to the axis L. However, the pair of upper and lower cam grooves 41, 46 may have different profiles, so that when the valve assembly 10 is displaced from the intermediate position to the first and second closed positions, the "shaft-side assembly" may be tilted with respect to the axis L.

[0073] The materials forming the components of the gate valve 1 according to this embodiment are not necessarily limited to those mentioned above, and any appropriate material can be used as needed. Furthermore, in this embodiment, the components of the power transmission mechanism 30 and the first and second cam frames 33, 34 are formed symmetrically in the thickness direction D and the width direction W, and as a result, the entire gate valve 1 is also formed substantially symmetrically in the width direction W and the thickness direction D, but this is not necessarily limited to this and each may be asymmetric. [Explanation of symbols]

[0074] 1. Gate valve 5. Bonnet 6 Valve shaft 6a Tip 6b Proximal end 10 Valve assembly 11 1st valve plate 12 2nd valve plate 20 Valve drive mechanism 21 Air cylinder section 22a First drive rod 23a Second drive rod 25 Guide Frame 30 Power transmission mechanism 31 First support frame 32 Second support frame 33 First Cam Frame 34 Second Cam Frame 35 Lever member 36 First spring member 37 Second spring member 40 1st opening / closing mechanism 41 First cam groove 41a First Recess 42 No. 1 Cam Roller 45 Second opening / closing mechanism 46 Second cam groove 46a Second relief 47 Second Cam Roller 50 First guide mechanism 51 First guide groove 52 First guide roller 55 Second guide mechanism 56 Second guide groove 57 Second guide roller 60 Stopper part S1,S2 starting position E1,E2 End position L axis

Claims

1. a gate valve disposed between a first chamber and a second chamber adjacent to each other, for connecting a first opening leading to the first chamber and a second opening leading to the second chamber to each other and for individually opening and closing the first opening and the second opening, The gate valve comprises a bonnet that divides the valve into an upper side and a lower side, a valve shaft that passes through the bonnet in an axial direction extending vertically and has a tip end and a base end disposed on the upper and lower sides of the bonnet, a valve assembly formed by attaching a first valve plate and a second valve plate to the tip end of the valve shaft with their backs facing each other, and a valve drive mechanism that is connected to the base end of the valve shaft and moves the valve assembly by operating the valve shaft, the valve drive mechanism includes a first drive rod and a second drive rod that can be driven independently, and an air cylinder unit that is fixed to the bonnet, and a power transmission mechanism that connects the first drive rod and the second drive rod to the valve shaft and transmits the drive force of the air cylinder unit to the valve shaft, whereby the valve assembly can be moved in the axial direction and in a thickness direction perpendicular to the axis to move to a first closing position for closing the first opening with the first valve plate, a second closing position for closing the second opening with the second valve plate, and a retracted position for connecting these openings to each other, the power transmission mechanism includes a first cam frame connected to the first drive rod and operating together with the first drive rod, a second cam frame connected to the second drive rod and operating together with the second drive rod, a lever member attached to a base end of the valve shaft, and a first opening / closing mechanism and a second opening / closing mechanism that individually reciprocate the valve assembly in the thickness direction, the first opening / closing mechanism has a first cam groove provided in either the first cam frame or the lever member, and a first cam roller provided in the other of them and slidably fitted in the first cam groove, and the second opening / closing mechanism has a second cam groove provided in either the second cam frame or the lever member, and a second cam roller provided in the other of them and slidably fitted in the second cam groove, the first cam roller reciprocates along the first cam groove in accordance with the reciprocating movement of the first drive rod, thereby causing the valve assembly to reciprocate in the thickness direction between a position occupied by the retracted position and a position occupied by the first closing position; and the second cam roller reciprocates along the second cam groove in accordance with the reciprocating movement of the second drive rod, thereby causing the valve assembly to reciprocate in the thickness direction between a position occupied by the retracted position and a position occupied by the second closing position, the gate valve has a width direction perpendicular to both the axial direction and the thickness direction, In the first opening / closing mechanism and the second opening / closing mechanism, the first and second cam frames are disposed on both sides of the lever member in the width direction, and further, the first and second cam frames are arranged side by side in the thickness direction on both sides of the lever member. A gate valve characterized by:

2. a first relief portion is formed in the first cam groove for allowing the first cam roller to escape when the valve assembly is moved to the second closed position, and a second relief portion is formed in the second cam groove for allowing the second cam roller to escape when the valve assembly is moved to the first closed position.

2. The gate valve according to claim 1.

3. the valve assembly is further movable in the axial direction to an intermediate position located between the retracted position and the first and second closing positions, the power transmission mechanism has a first spring member and a second spring member interposed between the first drive rod and the lever member, and a drive force of the first drive rod is transmitted to the lever member through the first spring member, and a drive force of the second drive rod is transmitted to the lever member through the second spring member, Furthermore, the power transmission mechanism has a stopper portion that stops the movement of the lever member in the axial direction when the valve assembly reaches an intermediate position from the retracted position by driving the air cylinder portion and allows the movement of the lever member in the thickness direction by the opening / closing mechanism, When the lever member is stopped from moving in the axial direction by the stopper portion, the first and second drive rods are individually driven, so that the opening and closing mechanism individually reciprocates the valve assembly between the intermediate position and the first and second closed positions.

2. The gate valve according to claim 1.

4. The intermediate position is provided at a position in the axial direction where the first and second closing positions are located.

4. The gate valve according to claim 3.

5. the gate valve has a width direction perpendicular to both the axial direction and the thickness direction, In the first opening / closing mechanism and the second opening / closing mechanism, the first and second cam frames are respectively disposed on both sides of the lever member in the width direction, and the first and second cam frames are respectively arranged side by side in the thickness direction on both sides of the lever member, and further, a first support frame and a second support frame are attached to the first driving rod and the second driving rod, and are connected to the lever member so as to be movable relative to the lever member, The pair of first cam frames are erected from the first support frame in the axial direction, and the first support frame and the lever member are connected by the first spring member between the pair of first cam frames in the width direction, and the pair of second cam frames are erected from the second support frame in the axial direction, and the second support frame and the lever member are connected by the second spring member between the pair of second cam frames in the width direction.

5. The gate valve according to claim 3 or 4.

6. a first relief portion is formed in the first cam groove for allowing the first cam roller to escape when the valve assembly is moved from the intermediate position to the second closed position, and a second relief portion is formed in the second cam groove for allowing the second cam roller to escape when the valve assembly is moved from the intermediate position to the first closed position.

6. The gate valve according to claim 5.

7. the power transmission mechanism further includes a guide frame fixedly provided to the bonnet, and first and second guide mechanisms provided between the guide frame and the first and second cam frames to guide movement of these cam frames in the axial direction, The first guide mechanism has a first guide groove provided in either the guide frame or the first cam frame along the axis, and a first guide roller provided in the other of the two and slidably fitted into the first guide groove, and the second guide mechanism has a second guide groove provided in either the guide frame or the second cam frame along the axis, and a second guide roller provided in the other of the two and slidably fitted into the second guide groove.

7. The gate valve according to claim 1, wherein the gate valve is a valve having a first opening and a second opening.

8. the guide frames are disposed on both sides of the lever member in the width direction, respectively, on the outer sides of the first and second cam frames arranged side by side in the thickness direction. A gate valve according to claim 7 which cites claim 5.

9. the air cylinder portions hang down from the bonnet along the axis on both sides of the lever member in the width direction, and the guide frames are respectively disposed inside the air cylinder portions in the width direction; In each of the pair of air cylinder portions, the first drive rod and the second drive rod are arranged side by side in the thickness direction, First drive rods of the pair of air cylinder units are attached to both end portions of the first support frame, and second drive rods of the pair of air cylinder units are attached to both end portions of the second support frame.

9. The gate valve according to claim 8.

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